%0 Journal Article
%A Greene, D.F.
%A Kneeshaw, D.D.
%A Messier, C.
%A Lieffers, V.
%A Cormier, D.
%A Doucet, R.
%A Coates, K.D.
%A Groot, A.
%A Grover, G.
%A Calogeropoulos, C.
%T Modelling silvicultural alternatives for conifer regeneration in boreal mixedwood stands (aspen/white spruce/balsam fir)
%B Forestry Chronicle
%D 2002
%V 78
%P 281-295
%N 2
%Z Cited By (since 1996): 19 Export Date: 6 March 2007 Source: Scopus; timestamp=(2007.12.05)
%X We model and compare the biological and financial constraints of four
prescriptions that serve as alternatives to conventional clearcutting
followed by planting in eastern and western boreal mixedwood stands.
These alternative prescriptions for full or partial conifer stocking
are (1) reliance on advance regeneration with or without augmentation
by fill-planting; (2) understory scarification during a mast year;
(3) direct seeding either aerially or with a scarifier-seeder; and
(4) underplanting. Our main conclusions concerning the biological
constraints are that (1) advance regeneration, mainly of balsam
fir in the east and white spruce in the west, requires >26 000 and
> 4000 trees/ha (because of different distributions), respectively,
to achieve full conifer stocking; (2) reliance on a mast year requires
at least 6 m2/ha of mature conifer basal area, but much less if
some advance regeneration is present or only moderate stocking is
desired; (3) aerial seeding with 35% scarification requires about
a half-million seeds/ha to achieve full conifer stocking, while
a scarifier-seeder would require only a third of this application
rate; and (4) underplanting is constrained to aspen stands with
>25% incident light at planting height. In all cases, alternative
prescriptions become more feasible if only moderate or minimal stocking
is the silvicultural objective. A costing exercise for the four
prescriptions in comparison with a clearcut followed by planting
shows that reliance on advance regeneration or understory planting
are the cheapest alternatives to achieve full or partial conifer
stocking. With the exception of full conifer stocking in situations
where there is little advance regeneration (and where herbicides
can be used), conventional plantations are never the cheapest approach.
In such cases, fill planting and use of a scarifier-seeder become
viable options. Aerial seeding and reliance on a mast year are the
most expensive of the alternatives. We conclude, tentatively, that
there is enough conifer basal area in most of the eastern boreal
mixedwood of Canada to allow for the use of either or both a mast
year and advance regeneration to achieve full or partial conifer
stocking. By contrast, in the west conifer basal area will seldom
be sufficient for natural seeding, and the density of advance regeneration
is likewise often too low. Finally, because of light constraints,
understory planting appears to have a much wider applicability in
the west than in the east.
%K Advance regeneration Balsam fir Boreal mixedwood silviculture Direct
seeding Understory planting Understory scarification White spruce
%# brugerolles
%F GreeneKneeshawMessierEtAl2002
%3 BibTeX type = ARTICLE